Solutions PYQs Set 2 (PDF)

Set 2 of 12 · Questions 31-60 of 332

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Mere Teacher · Previous Year Questions NEET Chemistry · Solutions · Set 2 (Q31-60)
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31. $Assertion: Standard boiling point of a liquid is slightly higher than the normal boiling point. Reason: 1 bar pressure is slightly less than 1 atm pressure.$ (1) $Assertion and Reason are correct statements and Reason is the correct explanation for Assertion.$ (2) $Assertion and Reason are correct statement and Reason is not the explanation for Assertion.$ (3) $Assertion is correct, Reason is incorrect.$ (4) $Assertion is incorrect, Reason is correct.$ 32. $The mixture that forms maximum boiling azeotrope is:$ (1) $Water + Nitric acid$ (2) $Ethanol + Water$ (3) $Acetone + Carbon disulphide$ (4) $Heptane + Octane$ 33. $Which of the following pair of solutions is isotonic?$ (1) $0.001 M Al_{2} (SO_{4})_{3} and 0.01 M BaCl_{2}$ (2) $0.001 M CaCl_{2} and 0.001 M Al_{2} (SO_{4})_{3}$ (3) $0.01 M BaCl_{2} and 0.001 M CaCl_{2}$ (4) $0.01 M BaCl_{2} and 0.015 MNaCl$ 34. $The empirical formula of a nonelectrolyte is CH_{2} O . A solution containing 3 g of the compound exerts the same osmotic pressure as that of 0.05 M glucose solution. The molecular formula of the compound is$ (1) $CH_{2} O$ (2) $C_{2} H_{4} O_{2}$ (3) $C_{4} H_{8} O_{4}$ (4) $C_{3} H_{6} O_{3}$ 35. $The vapour pressure of pure liquids A and B are 450 and 700 mm of Hg at 350 K respectively. If the total vapour pressure of the mixture is 600 mm of Hg, the composition of the mixture in the solution is$ (1) $x_{A} = 0.4, x_{B} = 0.6$ (2) $x_{A} = 0.6, x_{B} = 0.4$ (3) $x_{A} = 0.3, x_{B} = 0.7$ (4) $x_{A} = 0.7, x_{B} = 0.3$ 36. $What would be the molality of 20% (mass/mass) aqueous solution of Kl ? (molar mass of Kl = 166 g mol^{- 1})$ (1) $1.08$ (2) $1.35$ (3) $1.48$ (4) $1.51$ 37. $Molecules of benzoic acid (C_{6} H_{5} COOH) dimerise in benzene. ‘w’ g of the acid dissolved in 30 g of benzene shows a depression in freezing point equal to 2 K. If the percentage association of the acid to form dimer in the solution is 80 then w is : (Given that K_{f} = 5 K kg mol^{- 1} Molar mass of benzoic acid = 122 g mol^{- 1})$ (1) $2.4 g$ (2) $1.0 g$ (3) $1.5 g$ (4) $1.8 g$ 38. $According to Raoult’s law, the relative lowering of vapour pressure for a solution is equal to$ (1) $mole fraction of solute$ (2) $mole fraction of solvent$ (3) $moles of solute$ (4) $moles of solvent.$ 39. $What happens to freezing point of benzene when small quantity of napthalene is added to benzene?$ (1) $Increases$ (2) $Remains unchanged$ (3) $First decreases and then increases$ (4) $Decreases$ 40. $The boiling point of 0.2 mol k g^{- 1} solution of X in water is greater than equimolal solution of Y in water. Which one of the following statements is true in this case?$ (1) $Molecular mass of X is less than the molecular mass of Y .$ (2) $Y is undergoing dissociation in water while X undergoes no change.$ (3) $X is undergoing dissociation in water.$ (4) $Molecular mass of X is greater than the molecular mass of Y$ 41. $Which of the following aqueous solutions has the highest freezing point?$ (1) $0.01 MNaCl$ (2) $0.1 M Sucrose$ (3) $0.01 M Na_{2} SO_{4}$ (4) $0.1 MNaCl$ 42. $Of the following 0.10 m aqueous solutions, which one will exhibit the largest freezing point depression?$ (1) $KC1$ (2) $C_{6} H_{12} O_{6}$ (3) $A l_{2} (S O_{4})_{3}$ (4) $K_{2} S O_{4}$ 43. $At 80ºC, the vapour pressure of pure liquid 'A' is 520 mm Hg and that of pure liquid 'B' is 1000 mm Hg. If a mixture solution of 'A' and 'B' boils at 80ºC and 1 atm pressure, the amount of 'A' in the mixture is (1 atm = 760 mm Hg)$ (1) $34 mol percent$ (2) $48 mol percent$ (3) $50 mol percent$ (4) $52 mol percent$ 44. $Given below are two statements: Statement I : Gallium is used in the manufacturing of thermometers. Statement II : A thermometer containing gallium is useful for measuring the freezing point (256 K) of brine solution. In the light of the above statements, choose the correct answer from the options given below :$ (1) $Both Statement I and Statement II are true$ (2) $Statement I is false but Statement II is true$ (3) $Both Statement I and Statement II are false$ (4) $Statement I is true but Statement II is false$ 45. $A liquid mixture is an ideal solution, if (i) It obeys ideal gas equation (ii) It obeys Raoult's law at all concentrations (iii) Solute - solute, solute - solvent and solvent - solvent interactions are similar$ (1) $(i) only$ (2) $(i), (ii) only$ (3) $(ii), (iii) only$ (4) $(iii) only$ 46. $Liquid A and B form an ideal solution. The vapour pressures of pure liquids and are 350 and 750 mm Hg respectively at the same temperature. If and are the mole fraction of and in solution while and are the mole fraction of and in vapour phase, then,$ (1) $(x_{A} - y_{A}) < (x_{B} - y_{B})$ (2) $\frac{x _{A}}{x _{B}} = \frac{y _{A}}{y _{B}}$ (3) $\frac{x _{A}}{x _{B}} < \frac{y _{A}}{y _{B}}$ (4) $\frac{x _{A}}{x _{B}} > \frac{y _{A}}{y _{B}}$ 47. $The freezing point depression constant (K_{f}) of benzene is 5.12 Kkg mol^{- 1} . The freezing point depression for the solution of molality 0.078 m containing a non-electrolyte solute in benzene is (rounded off upto two decimal places) :$ (1) $0.80 K$ (2) $0.40 K$ (3) $0.60 K$ (4) $0.20 K$ 48. $5.0 g of sodium hydroxide (molar mass 40 g mol^{- 1}) is dissolved in little quantity of water and the solution is diluted up to 100 mL . What is the molarity of the resulting solution?$ (1) $0.1 mol dm^{- 3}$ (2) $1.0 mol dm^{- 3}$ (3) $0.125 mol dm^{- 3}$ (4) $1.25 mol dm^{- 3}$ 49. $Calculate the relative lowering of vapour pressure if the vapour pressure of benzene and vapour pressure of solution of non volatile solute in benzene are 640 mmHg and 590 mmHg respectively at same temperature.$ (1) $0.078$ (2) $0.175$ (3) $0.061$ (4) $0.092$ 50. $The vapour pressure of benzene at a certain temperature is 640 mm of Hg. A non‐volatile and non‐electrolyte solid, weighing 2.175 g is added to 39.08 of benzene. The vapour pressure of the solution is 600 mm of Hg. What is the molecular weight of solid substance?$ (1) $69.5$ (2) $59.6$ (3) $49.50$ (4) $79.8$ 51. $A 40 % HCl solution has density 1.2 g mL^{- 1} . The molarity of the solution is nearly\dots\dots\dots\dots$ (1) $11 M$ (2) $12 M$ (3) $13 M$ (4) $14 M$ 52. $If 8 g of a non-electrolyte solute is dissolved in 114 g of n -octane to reduce its vapour pressure to 80 %, the molar mass (in g mol^{- 1}) of the solute is [Given that molar mass of n-octane is 114 g mol^{- 1}]$ (1) $60$ (2) $80$ (3) $20$ (4) $40$ 53. $Which of the following will form an ideal solution?$ (1) $C_{2} H_{5} OH and H_{2} O$ (2) $HNO_{3} and H_{2} O$ (3) $CHCl_{3} and CH_{3} COCH_{3}$ (4) $C_{6} H_{6} and C_{6} H_{5} CH_{3}$ 54. $Assertion (A) : Blood cells collapse when suspended in saline waterReason (R) : Cell membrane dissolves in saline water$ (1) $Both (A) and (R) are correct and R is the correct explanation of A$ (2) $Both (A) and (R) are correct, but R is not the correct explanation of A$ (3) $(A) is correct but (R) is not correct$ (4) $(A) is incorrect but (R) is correct$ 55. $Relative lowering of vapour pressure of a dilute solution of glucose dissolved in 1 kg of water is 0.002 . The molality of the solution is$ (1) $0.004$ (2) $0.222$ (3) $0.111$ (4) $0.021$ 56. $A mixture of ethyl alcohol and propyl alcohol has a vapour pressure of 290 mm at 300 K. The vapour pressure of propyl alcohol is 200 mm. If the mole fraction of ethyl alcohol is 0.6, its vapour pressure (in mm) at the same temperature will be :$ (1) $700$ (2) $360$ (3) $350$ (4) $300$ 57. $Blood cells retain their normal shape in solution which are$ (1) $hypotonic to blood$ (2) $isotonic to blood$ (3) $hypertonic to blood$ (4) $equinormal to blood.$ 58. $of a compound, ' ' (molar mass ) is dissolved in of other compound, (molar mass = ). The ratio of mole fractions of and in the solution is$ (1) $1 : 5$ (2) $5 : 1$ (3) $4 : 1$ (4) $1 : 4$ 59. $At 50^{\circ} C, the vapour pressure of pure benzene is 268 torr The number of moles of non-volatile solute per mole of benzene required to prepare a solution having a vapour pressure of 167 torr at the same temperature is (molar mass of benzene = 78 g mol^{- 1})$ (1) $0.505$ (2) $0.705$ (3) $0.605$ (4) $0.405$ 60. $A solution containing 62 g ethylene glycol in 250 g water is cooled to - 10 ℃ . If K_{f} for water is 1.86 K kg mol^{- 1}, the amount of water (in g) separated as ice is :$ (1) $48$ (2) $32$ (3) $64$ (4) $16$